Linear Collider Flavour Identification Research Articles

Design and performance of improved Column Parallel CCD, CPC2

The Linear Collider Flavour Identification (LCFI) Collaboration is developing the sensors, readout electronics and mechanical support structures for the vertex detector of the International Linear Collider (ILC). High speed readout is needed to ensure that the occupancy due to the pair production background at the ILC is kept below the 1% level. In order to satisfy this requirement, Column Parallel CCDs (CPCCDs), Column Parallel Readout chips (CPRs) and Column Parallel Driver chips (CPDs) have been developed. The CPCCD has to operate at a clock frequency of 50MHz, which represents a difficult technical challenge due to the large sensor capacitance. The design and performance of the second generation CPCCD sensors, CPC2, and the new driver chip, CPD1, which meet these challenging requirements, are described.

Modeling of Radiation Hardness of a CCD with High-Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. An Analytic Model has been developed for the determination of the charge transfer inefficiency (CTI) of a CPCCD. The CTI values determined with the Analytic Model agree largely with those from a full TCAD simulation. The Analytic Model allows efficient study of the variation of the CTI on parameters like readout frequency, operating temperature and occupancy.

Comparison of Measurements of Charge Transfer Inefficiencies in a CCD With High-Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) Collaboration has been developing Column-Parallel CCDs for the vertex detector of a future Linear Collider which can be read out many times faster than standard CCDs. The most recent studies are of devices designed to reduce both the CCD's intergate capacitance and the clock voltages necessary to drive it. A comparative study of measured Charge Transfer Inefficiency values between our previous and new results for a range of operating temperatures is presented.

Charge shielding in the In-situ Storage Image Sensor for a vertex detector at the ILC

The Linear Collider Flavour Identification (LCFI) collaboration has successfully developed the first prototype of a novel particle detector, the In-situ Storage Image Sensor (ISIS). This device ideally suits the challenging requirements for the vertex detector at the future International Linear Collider (ILC), combining the charge storing capabilities of the Charge-Coupled Devices (CCD) with readout commonly used in CMOS imagers. The ISIS avoids the need for high-speed readout and offers low power operation combined with low noise, high immunity to electromagnetic interference and increased radiation hardness compared to typical CCDs. The ISIS is one of the most promising detector technologies for vertexing at the ILC. In this paper we describe the measurements on the charge-shielding properties of the p-well, which is used to protect the storage register from parasitic charge collection and is at the core of device's operation. We show that the p-well can suppress the parasitic charge collection by almost two orders of magnitude, satisfying the requirements for the application.

Modeling of Charge Transfer Inefficiency in a CCD With High-Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. An Analytic Model has been developed for the determination of the charge transfer inefficiency (CTI) of a CPCCD. The CTI values determined with the Analytic Model agree largely with those from a full TCAD simulation. The Analytic Model allows efficient study of the variation of the CTI on parameters like readout frequency, operating temperature and occupancy.

Measurements of Charge Transfer Inefficiency in a CCD With High-Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. A test stand for measuring the charge transfer inefficiency (CTI) of a prototype CPCCD has been set up. Studies of the CTI have been performed at a range of readout frequencies and operating temperatures.

Radiation hardness studies in a CCD with high-speed column parallel readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of the International Linear Collider (ILC). The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. The results of detailed simulations of the charge transfer inefficiency (CTI) of a prototype CPCCD including the variation of model parameters are reported. The effects of bulk radiation damage on the CTI of a CPCCD are studied by simulating the effects of two electron trap levels, 0.17 and 0.44 eV, at different concentrations and operating temperatures. The dependence of the CTI on different occupancy levels (percentage of hit pixels) and readout frequencies is also studied. The optimal operating temperature for the CPCCD, where the effects of the charge trapping are at a minimum, is found to be about 230 K for the range of readout speeds proposed for the ILC. The results of the full simulation have been compared with an analytic model.

Simulation of the charge transfer inefficiency of column parallel CCDs

Charge-Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layer make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column Parallel CCDs (CPCCDs) for the vertex detector of the International Linear Collider (ILC). The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. The results of detailed simulations of the Charge Transfer Inefficiency (CTI) of a prototype CPCCD chip are reported. The effects of the radiation damage on the CTI of a Si-based CCD particle detector are studied by simulating the effects of two electron trap levels Ec-0.17 and Ec-0.44 eV at different concentrations and operating temperatures. The dependence of the CTI on different occupancy levels (percentage of hit pixels) and readout frequencies is also studied. The optimal operating temperature—where the effects of the trapping are at a minimum—is found to be ∼230 K for the range of readout speeds proposed for the ILC.

Linear collider flavour identification status report: Sensors for the international linear collider

The Linear Collider Flavour Identification (LCFI) collaboration is continuing the work to develop column-parallel CCDs (CPCCD) and CMOS readout chips to be used in the vertex detector at the international linear collider (ILC). The CPCCD achieves several orders of magnitude faster readout than conventional CCDs because every column is equipped with amplifier and ADC, enabling efficient data taking with low occupancy. Already two generations of CPCCDs and readout chips have been manufactured and the first chips have been fully tested. The second generation devices are now being evaluated. A new CCD-based device, the in-situ storage image sensor (ISIS) has also been developed. The ISIS offers numerous advantages in terms of relaxed readout, increased radiation hardness and great immunity to EMI. In this paper we present the results from the tests of the CPCCDs, readout chips and ISIS, as well as the plans for future developments.

Radiation hardness of CCD vertex detectors for the ILC

Results of detailed simulations of the charge transfer inefficiency of a prototype CCD chip are reported. The effect of radiation damage in a particle detector operating at a future accelerator is studied by examining two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the 0.17 eV level. Optimum operation is predicted to be at about 250 K where the effect of the traps is minimal which is approximately independent of readout frequency. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project.

Progress with vertex detector sensors for the International Linear Collider

In the past year, the Linear Collider Flavour Identification (LCFI) Collaboration has taken significant steps towards having a sensor suitable for use in the silicon vertex detector of the International Linear Collider (ILC). The goal of the collaboration is to develop the sensors, electronic systems and mechanical support structures necessary for the construction of a high performance vertex detector and to investigate the contribution such a vertex detector can make to the physics accessible at the ILC. Particular highlights include the delivery and testing of both a second-generation column parallel CCD (CP-CCD), design of the next-generation readout ASIC (CPR2a) and a dedicated ASIC for driving the CP-CCD. This paper briefly describes these and other highlights.

Simulations of the Temperature Dependence of the Charge Transfer Inefficiency in a High-Speed CCD

Results of detailed simulations of the charge transfer inefficiency of a prototype serial readout CCD chip are reported. The effect of radiation damage on the chip operating in a particle detector at high frequency at a future accelerator is studied, specifically the creation of two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the former level but not for the latter. Optimum operation is predicted to be at about 250 K where the effects of the traps is minimal; this being approximately independent of readout frequency in the range 7-50 MHz. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project.

CCD-based vertex detector for ILC

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide a superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last few years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips, to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. The first set of prototype devices have been successfully designed, manufactured and tested, with second generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype has been manufactured.

CCD developments for particle colliders

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. First set of prototype devices have been designed, manufactured and successfully tested, with second-generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype is in production.

Recent results from R&D towards a vertex detector at the International Linear Collider

The linear collider flavour identification (LCFI) collaboration is performing an R&D program to develop a vertex detector for the International Linear Collider (ILC). Test results obtained with the first generation of sensors and their dedicated readout ASIC are reported. Plans for the second generation devices and the ISIS concept for the detector sensors are presented.

A vertex detector for the future linear collider

The Linear Collider Flavour Identification collaboration (LCFI) 1 1 Participating institutes: Bristol University, Lancaster University, Liverpool University, Oxford University, Queen Mary University London, Rutherford Appleton Laboratory. was formed in 1998 with the purpose of exploring a new design for a CCD pixel vertex detector, to be deployed at the future e+e − collider. A very ambitious R&D programme has been laid out, and funding has been officially confirmed recently. The programme will consist of multiple steps, the final goal being to produce a detector capable of being read out almost a thousand times faster than what has been done so far, with a material budget of less than 0.1% of a radiation length per layer and a polar angle coverage for tracks up to | cos ϑ|=0.96 . In these proceedings I will describe the new design in detail, and report on the status of the R&D project.

Flavour tagging at the future linear collider

Abstract High performance flavour tagging of jets containing heavy flavours is crucial for the studies planned for the future high energy e + e − Linear Collider (LC). Pixel detectors have proven to provide very powerful flavour identification, for this reason the Linear Collider Flavour Identification collaboration has decided to concentrate its R&D work for the future LC on a Charged Coupled Device pixel vertex detector, and study the flavour tagging performance of the design to optimize it. In this work we first evaluate the basic tracking performance. We then estimate the flavour tagging performance of the present detector layout, using a neural network approach. We conclude by studying the energy dependence of the performance.